1. Field of the Invention
The present invention relates to a display technical field, more particularly, relates to a thin film transistor, an array substrate, and a display apparatus.
2. Description of the Related Art
Generally, in a conventional thin film transistor (TFT) array substrate, as shown in FIG. 1, a TFT device is mainly composed of a gate electrode 1, an active layer 3, a source electrode 4 and a drain electrode 5 disposed on a substrate in this order. The gate electrode 1 is electrically isolated from the active layer 3 by a gate insulation layer 2. The source electrode 4 and the drain electrode 5 are formed in the same layer and opposite to each other by a single patterning process. A horizontal channel structure is formed in a region facing the gate electrode 1 between the source electrode 4 and the drain electrode 5. The source electrode 4 is electrically connected to a data line. The drain electrode 5 is electrically connected to a pixel electrode 7 through a via in a passivation layer 6. When the gate electrode 1 is loaded with a gate scan signal, the active layer 3 above the gate electrode 1 is converted from a semiconductor state to a conductor state, and a current channel is formed in a surface of the active layer 3 facing the insulation layer 2. The current channel is opposite to the horizontal channel structure formed between the source electrode 4 and the drain electrode 5. An electrical signal which is loaded from the data line to the source electrode 4 can be transmitted to the pixel electrode 7 through the drain electrode 5 by the current channel so as to activate pixel units.
It can be seen from the conventional thin film transistor (TFT) array substrate that a current flowing through the current channel formed in the active layer 3 is increased with the increase of the gate scan signal loaded on the gate electrode 1. When the current flowing through the current channel is large, the electrical signal loaded from the data line can control the pixel electrode 7 well, achieving a high image display quality. However, in practice, a voltage of the gate scan signal applied on the gate electrode 1 is limited by a power consumption of a display panel and cannot be set over high. Accordingly, in order to increase the current flowing through the current channel ‘a’ formed in the active layer 3, it is necessary to change the structure of the TFT device and enlarge the total area thereof, because the current flowing through the current channel formed in the active layer 3 is constrained by the size of the horizontal channel structure in some extent. Thereby, the horizontal channel structure having a large size can increase the current flowing through the current channel. However, the large-sized horizontal channel structure can cause a problem of decreasing an aperture ratio of pixel units.